The joy of a chest freezer is even though it may only have the same amount of space as an upright you'll still fit much bigger objects in with ease (husbands, kids, bailiffs that sort o thing
). On the whole though they tend to have a much bigger litreage than standard uprights.
If you are putting lambs and pigs in the freezer then the chest freezer would be my option for trying to fit in whole legs and large roasting joints. It does pay to be organised though or you end up discovering things in the bottom of the freezer like a pack of sausages that were reduced to clear several years before (Just under that traffic warden)!
The problem with the chest freezer is they can take up a fair bit of space, you really need a decent sized utility room for them to sit in if you are worried about the outside temperature aspect. That said, just about every farming family I know keeps the freezer in the garage or an outside shed somewhere. I have seen little ones though.
There is a good choice for buying them over the net. All the big electrical suppliers will happily take your money, if you shop around though there are some fantastic deals to be had on end of range models and lesser name brands.
Best o luck
p.s. Remember no matter how big a freezer you buy, or even how many you have you will still come home with the shopping and find that the freezer is already full and that there's not enough space for the bread!